Whether hunting or target shooting, it is not uncommon for a rifleman to have more than one weapon, each with its own load. As today's rifles become more sophisticated, it is virtually impossible for the user to memorize the detailed ballistic information needed to calculate the bullet drop for one or all of the rifles or loads he or she may use.
As evidenced by the prior art, it can be seen that there have been efforts made to provide sighting information on rifles. For example, U.S. Pat. No. 3,826,012 of Pachmayr discloses a gun sight attachable to a rifle which is adjustable to introduce a variable elevation correction into the sighting of a target, and has a scale or scales reading directly in terms of the proper gun to target distance for any particular setting of the sight.
U.S. Pat. No. 4,554,745 of Repa discloses a device attachable to a rifle for aligning an adjustable sight element in a sight system for rifles. The adjustable sight element within the sight system for rifles includes an aperture disc for a peep sight or an adjustable sight structure for a telescope sight. The adjustable sight element is adjustably mounted for movement about a vertical axis and a horizontal axis in a stationary housing attached to the rifle. The magnitude or degree of horizontal displacement of the adjustable sight element is indicated by a capacitance or optronic measuring device and is displayed digitally in electronic digital fields. The electronic component is located in a casing which is removably attached to the housing.
U.S. Pat. No. 4,561,204 of Binion discloses an opaque reticle display attachment for a rifle equipped with a telescopic sight. The user sights through the telescoping sight with his or her bore axis eye while simultaneously viewing an opaque reticle display screen which is aligned with his or her other eye. The display includes a cross-hairs aiming reticle. Transducers gather information relative to wind velocity and direction, ambient temperature, relative humidity, target elevation, and the like, which affect the ballistic trajectory of a projectile fired from the rifle. The information, alone or with range information, is fed to a microprocessor, which adjusts the position of the cross-hairs reticle on the display for proper aiming of the rifle. The user, by simultaneously viewing through the telescopic sight with one eye and viewing the opaque reticle display with the other eye, combines or superposes the two images into a single field of vision to aim the rifle in accordance with the position of the cross-hairs reticle.
None of these devices is completely satisfactory in providing a light weight, easy and inexpensive solution to the problem.
The applicant is aware of certain devices designed primarily for cutting and measuring. For example, U.S. Pat. No. 2,023,409 of Coll discloses a tape measure device that may be clamped to a pair of scissors. The attachment includes a cylindrical casing that holds a spool with a measuring tape thereon. A clamp to which the cylindrical casing is attached is capable of being clamped upon the shank of a pair of shears. Guide rollers within the cylindrical casing are positioned to be parallel to and adjacent with the blade of the shears, so that the user may measure the material to be cut while the shear is held at the point where the cutting is to begin.
U.S. Pat. No. 1,213,102 of Hill teaches a wrist mounted, spring wound tape measure. This invention discloses an apparatus of cylindrical formation having a hinged cover with a spring catch for securing the cover in a closed position upon the receptacle. The receptacle is designed to be mounted on a band or bracelet which attaches to the wrist of the user. The cover of the receptacle has a central opening so that a finger may touch the spring of a spring wound tape, which is arranged within the casing. The casing has a slot through which the tape may be drawn. In addition, a ring is attached to the end of the tape to prevent the end of the tape from being drawn into the casing.
U.S. Pat. No. 5,257,729 of Silver discloses a tool holder for securing a frequently accessed tool, such as a tape measure, to a user's wrist. The tool holder has a pouch that holds the tape measure, a strap attached to the pouch has loop type fasteners on opposite ends which are wrapped around the user's wrist to hold the strap in place. The pouch has access holes that allow extension and retraction of a tape measure blade so that the tape measure can be used while still attached to the user's wrist.
As seen by the prior art, devices have been developed that mount measuring tapes to instruments whose use often involves the need for measurement tapes. Also, devices have been mounted on firearms that aid in the calculation of firing a trajectory. However, it can be seen that none of them completely solve the problem of providing an easy and inexpensive way for the user of a rifle to calculate the proper aim of the rifle for varying loads and distances. The apparatus should be portable to various types of rifles, while the method of using the device remains the same.